#!/bin/sh
# -*- ruby -*-
exec "${RUBY-ruby}" "-x" "$0" "$@" && [ ] if false
#!ruby
# This needs ruby 2.0 and Git.
# As a Ruby committer, run this in a git repository to commit a change.

require 'tempfile'
require 'net/http'
require 'uri'
require 'shellwords'

ENV['LC_ALL'] = 'C'
ORIGIN = 'git@git.ruby-lang.org:ruby.git'
GITHUB = 'git@github.com:ruby/ruby.git'

class << Merger = Object.new
  def help
    puts <<-HELP
\e[1msimple backport\e[0m
  ruby #$0 1234abc

\e[1mrevision increment\e[0m
  ruby #$0 revisionup

\e[1mteeny increment\e[0m
  ruby #$0 teenyup

\e[1mtagging major release\e[0m
  ruby #$0 tag 3.2.0

\e[1mtagging patch release\e[0m (for 2.1.0 or later, it means X.Y.Z (Z > 0) release)
  ruby #$0 tag

\e[1mtagging preview/RC\e[0m
  ruby #$0 tag 3.2.0-preview1

\e[1mremove tag\e[0m
  ruby #$0 removetag 3.2.9

\e[33;1m* all operations shall be applied to the working directory.\e[0m
    HELP
  end

  def interactive(str, editfile = nil)
    loop do
      yield if block_given?
      STDERR.puts "\e[1;33m#{str} ([y]es|[a]bort|[r]etry#{'|[e]dit' if editfile})\e[0m"
      case STDIN.gets
      when /\Aa/i then exit 1
      when /\Ar/i then redo
      when /\Ay/i then break
      when /\Ae/i then system(ENV['EDITOR'], editfile)
      else exit 1
      end
    end
  end

  def version_up(teeny: false)
    now = Time.now
    now = now.localtime(9*60*60) # server is Japan Standard Time +09:00
    system('git', 'checkout', 'HEAD', 'version.h')
    v, pl = version

    if teeny
      v[2].succ!
    end
    if pl != '-1' # trunk does not have patchlevel
      pl.succ!
    end

    str = open('version.h', 'rb', &:read)
    ruby_release_date = str[/RUBY_RELEASE_YEAR_STR"-"RUBY_RELEASE_MONTH_STR"-"RUBY_RELEASE_DAY_STR/] || now.strftime('"%Y-%m-%d"')
    [%W[RUBY_VERSION      "#{v.join('.')}"],
     %W[RUBY_VERSION_CODE  #{v.join('')}],
     %W[RUBY_VERSION_MAJOR #{v[0]}],
     %W[RUBY_VERSION_MINOR #{v[1]}],
     %W[RUBY_VERSION_TEENY #{v[2]}],
     %W[RUBY_RELEASE_DATE #{ruby_release_date}],
     %W[RUBY_RELEASE_CODE  #{now.strftime('%Y%m%d')}],
     %W[RUBY_PATCHLEVEL    #{pl}],
     %W[RUBY_RELEASE_YEAR  #{now.year}],
     %W[RUBY_RELEASE_MONTH #{now.month}],
     %W[RUBY_RELEASE_DAY   #{now.day}],
    ].each do |(k, i)|
      str.sub!(/^(#define\s+#{k}\s+).*$/, "\\1#{i}")
    end
    str.sub!(/\s+\z/m, '')
    fn = sprintf('version.h.tmp.%032b', rand(1 << 31))
    File.rename('version.h', fn)
    open('version.h', 'wb') do |f|
      f.puts(str)
    end
    File.unlink(fn)
  end

  def tag(relname)
    # relname:
    #   * 2.2.0-preview1
    #   * 2.2.0-rc1
    #   * 2.2.0
    v, pl = version
    if relname
      abort "patchlevel is not -1 but '#{pl}' for preview or rc" if pl != '-1' && /-(?:preview|rc)/ =~ relname
      abort "patchlevel is not 0 but '#{pl}' for the first release" if pl != '0' && relname.end_with?(".0")
      pl = relname[/-(.*)\z/, 1]
      curver = "#{v.join('.')}#{("-#{pl}" if pl)}"
      if relname != curver
        abort "given relname '#{relname}' conflicts current version '#{curver}'"
      end
    else
      if pl == '-1'
        abort 'no relname is given and not in a release branch even if this is patch release'
      end
    end
    tagname = "v#{v.join('_')}#{("_#{pl}" if v[0] < "2" || (v[0] == "2" && v[1] < "1") || /^(?:preview|rc)/ =~ pl)}"

    unless execute('git', 'diff', '--exit-code')
      abort 'uncommitted changes'
    end
    unless execute('git', 'tag', tagname)
      abort 'specfied tag already exists. check tag name and remove it if you want to force re-tagging'
    end
    execute('git', 'push', ORIGIN, tagname, interactive: true)
  end

  def remove_tag(relname)
    # relname:
    #   * 2.2.0-preview1
    #   * 2.2.0-rc1
    #   * 2.2.0
    #   * v2_2_0_preview1
    #   * v2_2_0_rc1
    #   * v2_2_0
    unless relname
      raise ArgumentError, 'relname is not specified'
    end
    if /^v/ !~ relname
      tagname = "v#{relname.gsub(/[.-]/, '_')}"
    else
      tagname = relname
    end

    execute('git', 'tag', '-d', tagname)
    execute('git', 'push', ORIGIN, ":#{tagname}", interactive: true)
    execute('git', 'push', GITHUB, ":#{tagname}", interactive: true)
  end

  def update_revision_h
    execute('ruby tool/file2lastrev.rb --revision.h . > revision.tmp')
    execute('tool/ifchange', '--timestamp=.revision.time', 'revision.h', 'revision.tmp')
    execute('rm', '-f', 'revision.tmp')
  end

  def stat
    `git status --short`
  end

  def diff(file = nil)
    command = %w[git diff --color HEAD]
    IO.popen(command + [file].compact, &:read)
  end

  def commit(file)
    current_branch = IO.popen(['git', 'rev-parse', '--abbrev-ref', 'HEAD'], &:read).strip
    execute('git', 'add', '.') && execute('git', 'commit', '-F', file)
  end

  def has_conflicts?
    changes = IO.popen(%w[git status --porcelain -z]) { |io| io.readlines("\0", chomp: true) }
    # Discover unmerged files
    # AU: unmerged, added by us
    # DU: unmerged, deleted by us
    # UU: unmerged, both modified
    # AA: unmerged, both added
    conflict = changes.grep(/\A(?:.U|AA) /) {$'}
    !conflict.empty?
  end

  private

  # Prints the version of Ruby found in version.h
  def version
    v = p = nil
    open 'version.h', 'rb' do |f|
      f.each_line do |l|
        case l
        when /^#define RUBY_VERSION "(\d+)\.(\d+)\.(\d+)"$/
          v = $~.captures
        when /^#define RUBY_VERSION_TEENY (\d+)$/
          (v ||= [])[2] = $1
        when /^#define RUBY_PATCHLEVEL (-?\d+)$/
          p = $1
        end
      end
    end
    if v and !v[0]
      open 'include/ruby/version.h', 'rb' do |f|
        f.each_line do |l|
          case l
          when /^#define RUBY_API_VERSION_MAJOR (\d+)/
            v[0] = $1
          when /^#define RUBY_API_VERSION_MINOR (\d+)/
            v[1] = $1
          end
        end
      end
    end
    return v, p
  end

  def execute(*cmd, interactive: false)
    if interactive
      Merger.interactive("OK?: #{cmd.shelljoin}")
    end
    puts "+ #{cmd.shelljoin}"
    system(*cmd)
  end
end

case ARGV[0]
when "teenyup"
  Merger.version_up(teeny: true)
  puts Merger.diff('version.h')
when "up", /\A(ver|version|rev|revision|lv|level|patch\s*level)\s*up\z/
  Merger.version_up
  puts Merger.diff('version.h')
when "tag"
  Merger.tag(ARGV[1])
when /\A(?:remove|rm|del)_?tag\z/
  Merger.remove_tag(ARGV[1])
when nil, "-h", "--help"
  Merger.help
  exit
else
  Merger.update_revision_h

  case ARGV[0]
  when /--ticket=(.*)/
    tickets = $1.split(/,/)
    ARGV.shift
  else
    tickets = []
    detect_ticket = true
  end

  revstr = ARGV[0].gsub(%r!https://github\.com/ruby/ruby/commit/|https://bugs\.ruby-lang\.org/projects/ruby-master/repository/git/revisions/!, '')
  revstr = revstr.delete('^, :\-0-9a-fA-F')
  revs = revstr.split(/[,\s]+/)
  commit_message = ''

  revs.each do |rev|
    git_rev = nil
    case rev
    when /\A\h{7,40}\z/
      git_rev = rev
    when nil then
      puts "#$0 revision"
      exit
    else
      puts "invalid revision part '#{rev}' in '#{ARGV[0]}'"
      exit
    end

    # Merge revision from Git patch
    git_uri = "https://github.com/ruby/ruby/commit/#{git_rev}.patch"
    resp = Net::HTTP.get_response(URI(git_uri))
    if resp.code != '200'
      abort "'#{git_uri}' returned status '#{resp.code}':\n#{resp.body}"
    end
    patch = resp.body.sub(/^diff --git a\/version\.h b\/version\.h\nindex .*\n--- a\/version\.h\n\+\+\+ b\/version\.h\n@@ .* @@\n(?:[-\+ ].*\n|\n)+/, '')

    if detect_ticket
      tickets += patch.scan(/\[(?:Bug|Feature|Misc) #(\d+)\]/i).map(&:first)
    end

    message = "#{(patch[/^Subject: (.*)\n---\n /m, 1] || "Message not found for revision: #{git_rev}\n")}"
    message.gsub!(/\G(.*)\n( .*)/, "\\1\\2")
    message = "\n\n#{message}"

    puts '+ git apply'
    IO.popen(['git', 'apply', '--3way'], 'wb') { |f| f.write(patch) }

    commit_message << message.sub(/\A-+\nr.*/, '').sub(/\n-+\n\z/, '').gsub(/^./, "\t\\&")
  end

  if Merger.diff.empty?
    Merger.interactive('Nothing is modified, right?')
  end

  Merger.version_up
  f = Tempfile.new 'merger.rb'
  f.printf "merge revision(s) %s:%s", revs.join(', '), tickets.map{|num| " [Backport ##{num}]"}.join
  f.write commit_message
  f.flush
  f.close

  if Merger.has_conflicts?
    Merger.interactive('conflicts resolved?', f.path) do
      IO.popen(ENV['PAGER'] || ['less', '-R'], 'w') do |g|
        g << Merger.stat
        g << "\n\n"
        f.open
        g << f.read
        f.close
        g << "\n\n"
        g << Merger.diff
      end
    end
  end

  unless Merger.commit(f.path)
    puts 'commit failed; try again.'
  end

  f.close(true)
end
